1. Field of the Invention
The present invention relates to a semiconductor device and a method of forming the same, and more particularly, to a semiconductor device having a magnetoresistive random access memory, (MRAM) structure and a forming method thereof.
2. Description of the Prior Art
Magnetoresistive random access memory (MRAM) is a non-volatile computer memory technology, and is about six times faster than the current industry-standard memory, dynamic RAM (DRAM). Since the MRAM usually include functions like high speed data transmission, high density, light size, low power consumption and impact resistance, it is particularly suitable to apply to advanced portable electronic products, such as smart mobile phones.
Unlike these technologies, MRAM uses magnetism instead of electrical charges to store data. In general, the MRAM cells include a data layer and a reference layer. The data layer is composed of a magnetic material and during a write operation the magnetization of the data layer can be switched between two opposing states by an applied magnetic field and thus binary information can be stored. The reference layer usually is composed of a magnetic material in which the magnetization is pinned so that the magnetic field, which is applied to the data layer and in part penetrates the reference layer, is of insufficient strength to switch the magnetization in the reference layer. Unlike the DRAM, the MRAM does not require a transistor for the write operation. It is generally believed that MRAM will have to move to the 65 nm size of the most advanced memory devices, which will require the use of spin-torque-transfer (STT) technology.
However, the prior art MRAM still has several drawbacks. Therefore, there is a need in this industry to provide an improved method for fabricating the MRAM devices in order to avoid the aforementioned problems.